Electric switch and door interlock operating mechanism

ABSTRACT

A switch and door interlock operating mechanism for a door that has a vault-type door locking mechanism. The mechanism includes an operating assembly that is mounted on the front surface of the door by concealed screws that also position a hinged support for a switch. The hinged support is rotatable to a position which will permit ready access to the terminals of the switch and positions the switch so that the buttons of the switch are aligned with a lever of the operator so the switch may be actuated from the front side of the door. The operator also has a connection with an interlock lever which will prevent opening of the door when the switch is turned on by the operator.

Armand G. Mueller, Wauwatosa; Orval C. Bast, Milwaukee;

United States Patent [72] Inventors 3,496,316 2/1970 Foerstner..................... ZOO/50A William H. Schmeling, wauwamsa, a of wis- Primary Examiner V. Truhe Assistant ExaminerGale R. Peterson Attorneys-Harold .l. Rathbun and William H. Schmeling [73] Assignee Square D. Company Park Ridge, Ill.

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side of the door. The operator also has a connection with an interlock lever which will prevent o the switch is turned on by the operat pening of the door when PATENTEU'Nuv 16 Ian SHEET 1 [1F 2 ELECTRIC SWITCH AND DOOR INTERLOCK OPERATING MECHANISM This invention relates to operating mechanisms for-enclosures and is more particularly concernedwith an operating mechanism for a switch and a door interlock mechanism which will prevent opening of the door of an enclosure while the switch is on.

Industrial safety practices frequently require enclosures housing electrical equipment be provided with arrangements which will prevent the opening of the enclosure door while the electrical equipment is energized. An additional requirement imposed upon the equipment is that the connection between the operating handle and the switch be constantly maintained when the door is opened. A structure satisfying these requirements is illustrated in a US. Pat. No. 3,059,072 which was granted to the inventors Earl F. Mekelburg and Otto Frey on Oct. [6, 1962. In the Mekelburg et al. patent, an operator mounted on a fixed flange located on one side of the enclosure door provides an operating connection to a switch within the enclosure and an interlock means which assures that the door is closed and cannot be opened when the switch is in an ON position. However, in certain installations it may be desirable to mount a switch on the door and to provide an interlock between the switch-operating mechanism and the door-interlocking mechanism so that the door cannot be opened when the switch is in the ON condition. Further, it is desirable that the switch be accessible for wiring and servicing purposes and that the structure be tamper-proof, as well as provide a pleasing appearance to the exterior of the enclosure.

It is an object of the present invention to provide a door interlock and a switch-operating mechanism that is mounted on an internal surface of an enclosure door which will prevent opening of the door when the switch is dition.

An additional object is to provide a switch operator and door-interlock-operating mechanism for an enclosure which is mounted on the door for the enclosure and includes a means which is positionable to lock the operating mechanism in either the ON or the OFF switch positions and the interlock mechanism in a disabled position or a position which will prevent opening of the door when the switch is in an ON position.

A further object is to provide an operating mechanism which may be mounted on the door of an enclosure for electrical equipment and includes an operator assembly that is mounted on the front surface of the door, a switch assembly including a switch support that is hingedly mounted on the rear surface of the door by screws which also position the operator assembly on the front surface of the door and a locking means which is operative to prevent opening of the door whenever the operator assembly turns the switch to the ON position.

An additional object is to provide an operating mechanism which may be mounted on the door of an enclosure for electrical equipment and includes an operator assembly that is mounted on the front surface of the door, a switch assembly including a support for a switch that is hingedly mounted on the rear surface of the door by screws which also position the operator assembly on the front surface of the door and a locking means which is operative to prevent opening of the door whenever the operator assembly turns the switch to the ON position and wherein the operator assembly is provided with a selectively positionable lockout which will prevent the operator from being moved from one position to another position and the locking means includes a rod that is adjustable in length.

Further objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawing illustrating certain preferred embodiments in which:

FIG. I is a side elevational view of a portion of a switch cabinet with the door open to illustrate a rear view of the switch and interlock operating mechanism according to the present invention.

in a circuit making con- FIG. 2 is a top end view of the switch and interlock mechanism in FIG. 1 with a portion of the operator assembly shown in cross section and portion of the switch support assembly broken away to illustrate the operative connection between the operator assembly and the interlock operator.

FIG. 3 is a side view of the switch and interlock mechanism in FIG. I with a portion of the door shown in cross section and a portion of the operator assembly broken away to illustrate the connection between the operator assembly and the interlock operator.

FIG. 4 is an exploded view showing in perspective the lever and handle arrangement in the operator assembly in FIGS. 1-3 as well as the connection with the interlock operator.

FIG. 5 is a plan view of a locking plate incorporated in the assembly shown in FIGS. 2 and 3.

In the drawings,.a numeral 10 designates an enclosure that has a front opening 12 closeable by a door 14. The door 14 is mounted by hinges 16 on the enclosure 10 and when open, provides access to the interior of the enclosure wherein electrical devices 18 are mounted. The electrical devices 18 may include starters, relays, contactors, solid state type logic units and power supplies for the logic units, all of which are well known to those skilled in the art. The electrical devices I8, as in conventional practice, have wires connected thereto by means of terminals so that inadvertent contact with the terminals while the devices are energized may result in injury or death to persons inspecting or servicing the devices. For this reason, modern safety practices require that the electrical devices be deenergized at all times when the door is open.

The door 14 is maintained in a closed position by a vaulttype door-locking mechanism 20 that includes a member 22 that is rotatable about a pivot 24, a pair of rods 26 and 28 which are secured to the member 22 on opposite sides of the pivot 24 and extend upwardly and downwardly along a rear surface 44 of the door 14, and a finger 30 extending from the member 22. The plate member 22 is rotatable by a handle, not shown, located on a front surface rotated clockwise to the position shown in FIG. I, wherein the rods 26 and 28 are extended upwardly and downwardly beyond the outer marginal edges of the door 14 to engage inner surfaces of a flange surrounding the opening I2 to maintain the door 14 against movement relative to the enclosure 10. The finger 30 likewise moves with the member 22 to the position shown in FIG. 1 to engage the inner surface of the flange and maintain the central portion of the door 14 in tight engagement with the enclosure 10.

A switch and interlock operating mechanism 32 according to the present invention is mounted on the door 14 and includes an operator assembly 34, a switch support assembly 36 and an interlock mechanism 38. The door 14 has an opening 40 extending between the front surface 42 and the rear surface 44. The opening 40 is located at the upper left corner of the door 14 when the door is viewed as in FIG. I.

The switch support assembly 36 includes a mounting plate 46 and a switch support member 48. The mounting plate 46 has a central opening 50 and a pair of hinges 52 secured on one side of the plate 46 and a pair of upstanding ears 54 on its opposite side. The switch support member 48 is boxlike in character, presenting a pair of sides 56 and 58 that extend from a surface 60. The side 56 is secured to the pair of hinges 52 so that the entire switch support member 48 may be rotated about the hinges 52 from the position shown in FIG. 2 wherein the surface 60 extends parallel to the mounting plate 46 in a counterclockwise direction to a position wherein the surface 60 extends substantially perpendicular to the mounting plate 46. The side 58 has a pair of ears 64 which are aligned with the ears 54. The ears 64 are provided with openings which will permit screws 66 to be threaded into openings in the ears 54 to secure the switch support member 48 in the position shown in FIG. 2. When the screws 66 are detached, the switch support member 48 may be rotated about the hinges 52. Secured on surface 60 is a switch 62 which is of the manually operated type and includes an OFF 42 of the door 14 so as to be pushbutton 70 and an ON pushbutton 72. The OFF pushbutton 70 and the ON pushbutton 72 are aligned in a plane 74 that is perpendicular to the surface 60 as well as the mounting plate 46 when the switch support member 48 is secured by the screws 66. The switch 62, as illustrated. preferably is of the type commonly known as a manually operated motor starter and is of the form disclosed in an application for US. Pat., Ser. No. 9,203, which was filedon Feb. 6, 1970 and has been assigned by the inventor Jordan M. Puetz to the assignee of the present invention. As disclosed in the Puetz application, the buttons 70 and 72 respectively have operating ends 76 and 78 which are movable in a line of movement that extends in the plane 74 so as to move a contact carrier and movable contacts within the switch 62 to a position wherein the movable contacts are separated from the stationary contacts of the switch 62 so that the switch is in an OFF condition and to a position wherein the movable contacts engage the stationary contacts so as to complete a circuit therebetween and thereby cause the switch 62 to be in an ON position. When the OFF button 70 is depressed, the contacts for the switch 62 will be in the open position and when the ON pushbutton 72 is depressed, the contacts of the switch will be in a circuit closing position. Positioned on the front surface 42 is the operator assembly 34. The operator assembly 34 includes a housing 80 which is preferably formed of a die-cast metal although if desired, the housing 80 may be formed of a suitable thermoplastic or thermosetting plastic material. The housing 80 is secured to the front surface 42 by suitable screws 82 which also secure the mounting plate 46 to the rear surface 44. The screws 82 extend through openings in the mounting plate 46 and openings in the door 14 and are threadedly received into threaded openings in the housing 80 when the opening 50 and the opening 40 are in alignment with each other. The housing 80 has an internal cavity 84. The cavity 84 faces the opening 40 and has a wall 86 which conceals the opening 40. The wall 86 is arranged to be spaced from the operating ends 76 and 78 of the pushbuttons 70 and 72. Extending into a front surface and a sidewall of the housing 80 is a triangularly shaped indentation 88. The indentation 88 is provided with a triangularly shaped groove 90 that extends along an axis that is parallel to the plane 74. Extending through the sidewall of the housing 80 from the indentation 88 is a bore 92. Positioned by the bore 92 is a means 94 for selectively moving the pair of spaced pushbuttons 70 and 72 in respective lines of movement. As shown in FIG. 4, the means 94 includes a shaft 96, a handle 98, a lever 100, an O-ring seal 102 and a C-ring 104. Additionally, the means 94 includes a means for selectively preventing the movement of the handle 98 from one position to another position which includes a locking plate 106 that has a pair of openings located therein to function in a manner described in an application for U.S. Pat., Ser. No. 9,161, which was filed by the inventors Lewis M. Lehman and John R. Stauder on Feb. 6, 1970 and assigned to the assignee of the present invention.

Extending inwardly into the cavity 84 located on opposite sides of the plane 74 from the wall 86 are a pair of bosses 108 and 110. The boss 108 has a cylindrical socket 112 which is centered on the axis of the bore 92. The boss 110 has a free end wherein a hemispherical groove is disposed. The hemispherical groove is similarly centered on the axis of the bore 92. The shaft 96 has a length sufficient to permit a cylindrical portion 114 on an end of the shaft 96 to be journaled within the socket 112 while a portion, not shown, on the opposite end of the shaft 96 which has the handle 98 nonrotatably secured thereon, positions the handle 98 within the indentation 88. A portion of the shaft 96 received within the bore 92 is suitably grooved to receive the O-ring seal 102. The O-ring seal 102 prevents the entrance of fluids and dust from the exterior of the housing 80 into the cavity 84. A portion of the shaft 96 designated by a numeral 118 is shaped to provide a nonrotatable connection between the shaft 96 and the lever 100 and permit the shaft 96 to be detached from the lever 100. This result is accomplished by truncating the opposite sides of the shaft 96 at the portion 118 and providing a similarly shaped bore 120 within the lever which receives the shaft 96 so that the lever 100 and the shafi 96 may be separated by sliding the lever 100 on the shaft 96 and withdrawing the end portion 118 from the bore 120. The lever 100 is positioned between the bosses 108 and to be rotated by the shaft 96. The truncated portions 118 of the shaft 96 are arranged so that the lever 100 extends substantially perpendicular to the handle 98. The shaft is positioned against removal from the bore 92 by the C-ring 104. The C-ring 104 is received in a suitable groove in the shaft 96 that is located in the shaft 96 so a surface of the C-ring is positioned adjacent the wall portion of the housing 80. The removal of the C-ring 104 from its groove will permit the shaft 96 to be slidably moved to the left, as in FIG. 2, as the portion 118 slides in the noncircular bore 120. The lever 100 has arm portions 122 and 124 extending in substantially opposite directions from the shaft 96. As shown, the arm portions 122 and 124 are slightly inclined to provide free ends 126 and 128 which are arranged to engage the ends 76 and 78 to move the buttons 70 and 72 in the respective lines of movement when the shaft 96 rotates between two positions as dictated by the oscillating movement of the handle 98 within the indentation 88.

The indentation 88 is triangularly shaped and extends in a plane perpendicular to the front wall of the housing 80. The locking plate 16, as shown in FIG. 5, is shaped to be received in the groove 90 and has a pair of edges 130 and 132 and a rounded apex 134 which are congruent to the walls and an apex of the groove 90 so that the plate 106 may be received in either of two selected positions in the groove 90. An opening 136, located in the plate 106 along a line that bisects the angle defined by the edges 130 and 132, is located to be aligned with the bore 92 to permit a portion of the shaft 96 to extend through the opening 136 when the locking plate 106 is in either of its two positions in the groove 90. An opening 138 in the plate 106 is displaced from the bisecting line that extends through the opening 136 and is located so that at least a portion of the opening 138 projects forwardly of the front surface of the housing 80 when the plate 106 is in either of its two positions in the groove 90. Thus when the plate 106 is positioned in the groove 90 in one of its selected position, the opening 138 will be located to prevent movement of the operating handle 98 from the OFF position to the ON position when the shackle of a padlock, not shown, is passed through the opening 138. Additionally, when the plate 106 is positioned in the groove 90 in the other of its selected positions, the opening 138 will be located to receive the shackle of a padlock and prevent the movement of the operating handle 98 from the ON position to the OFF position. The position of the locking plate 106 in the groove 90 may be readily changed by merely removing the C-ring 104 from its groove in the shaft 96 and removing a pin 168, as will be later described, from its threaded opening in the shaft 96, so that the shaft 96 may be withdrawn from the bore 92. When the shaft 96 and a handle 98 are thus removed, the lever 100 will be detached from the shaft 96 and the position of the locking plate 106 may be reversed in the groove 90. After the locking plate 106 is repositioned in the groove 90, the shaft 96 may be reinserted through the opening 136 into the bore 92 and into its position wherein the portion 114 of the shaft is received in the socket 112. The shaft 96 together with the lever 100 and the handle 98 are maintained assembled with the housing 80 when the C- ring 104 is reinserted in the groove in the shaft 96 so that the operator assembly 34 may be readily converted to maintain the handle 98 in either its ON position or its OFF position.

A means 140 for preventing movement of the locking mechanism 20 to a position which will permit opening the door 14 while the handle 98 and the switch 62 are in the ON position includes a latch assembly 142 and an operating assembly 144. The latch assembly includes a latch plate 146, a torsion spring 148 and a manually operated defeater 150. The manually operated defeater includes a sleeve, not shown, that is nonrotatably mounted on the door. Extending through the sleeve is a rotatable pin 152 which on the front side of the door 14 has a slot, not shown, which may be used to rotate the pin 152 manually when a screwdriver tip is inserted in the slot. The latch plate 146 is secured on the end of the pin 152 that extends beyond the sleeve on the rear surface so as to rotate with the pin 152 when the pin 152 is rotated by a screwdriver. The latch plate 146 has a finger 154 along its upper edge that extends toward the surface 44 and an arcuate slot 156 extending concentric to the pin 152. The pin 152 also acts as a pivot for the latch plate 146. Extending outwardly of the rear surface 44 is a pin 158 that has an end received in the slot 156. The torsion spring 148, which has its convolutions surrounding the sleeve wherein the pin 152 is received, has one end positioned against the pin 158 and its other end positioned against the finger 154. The torsion spring 148 is arranged to constantly urge the latch plate 146 to the position shown in FIG. 1. The latch plate 146 and the rotatable member 22, as shown in FIG. 1, are mounted on the rear surface 44 to have an edge 160 on the latch plate 146 positioned to be engaged by an edge 162 on the rotatable member 22 and thus obstruct and prevent the rotation of the member 22 from its locking position when the member 22 is in the position shown in FIG. 1 and thus prevent the door 14 from being moved to its open position. The latch plate 146 has a threaded opening therein which receives a screw 164.

The operating assembly 144 includes a rod 166 and a motion transmitting pin 168.

The pin 168 is threaded into a threaded opening 170 in the shaft 96 so a portion projects from the surface of the shaft 96 and extends to duplicate the oscillating movement of the handle 98. Thus when the handle 98 is rotated to its upward position shown in FIG. 3 to actuate the ON pushbutton 72, the pin 168 will extend upwardly. When the handle 98 is rotated in a counterclockwise direction to extend downwardly, and actuate the OFF pushbutton 70, the pin 168 will extend downwardly and be in a position not shown, but evident in FIG. 3. The rod 166 is formed in two sections which are interconnected by an adjuster 170. The adjuster 170 receives the threaded ends of the sections of the rod 166 so the operating length of the rod 166 is made adjustable to assure proper operation of the interlock mechanism 38. The upper end of the rod 166 has an opening 172 which receives the projecting end of pin 168. The lower end of the rod 166 has an elongated slot 174 in flattened portion 176. The slot receives the screw 164 so the rod 166 is attached to the latch plate 146 with a lost-motion connection. The rod 166 is suitably shaped to have a major portion extending parallel to the rear surface 44 and a portion passing through the openings 40 and 50 so the portion wherein the opening 172 is located is positioned between the wall 86 and the shaft 96 when the pin 168 is received in the opening 172.

The upper and lower ends of the switch support member 48 are provided with flanges 178 to add rigidity to the switch support member 48. The switch 62, as disclosed in the Puetz application supra, is provided with wire conducting terminals 180 at its upper and lower ends which are connected through suitable wires 182 to the electrical devices 18 within the enclosure so that the operation of the devices 18 may be controlled by the switch 62 in a manner well known to those skilled in the art. When the switch support member 48 is positioned as in FIG. 2, the operating buttons 70 and 72 will be positioned to be actuated by the lever 100 and access to the terminals 180 will be effectively prevented as the switch 62 is positioned between the surface 60 and the rear surface 44. During wiring or servicing of the switch 62, the screws 66 are loosened so that the switch support member 48 may be rotated about the hinge 52 to a position wherein the surface 60 extends substantially perpendicular to the rear surface 44 thereby providing ready access to the screws of the terminals 180 so that the switch may be wired without difficulty. Further, if it is required that the components of the switch be serviced, ready access is provided thereto through the unobstructed front opening which is provided between the sides 56 and 58 of the switch support member 48.

When the door-locking mechanism 20 and the switch and interlock mechanism 32 are positioned as in FIG. 1, the rods 26 and 28 as well as the finger 30 will be positioned to prevent opening of the door and the door-locking mechanism 20 will be prevented from being moved to a position which would permit the door to be opened by the edges 160 and 162 of the latch plate 146 and the member 22. If it is desired to open the door while the switch is in the ON position, the function of the interlock mechanism 32 may be defeated when a screwdriver, which is inserted into the slot in the pin 152 that is exposed to the front surface 42, is used to rotate the latch plate 146 against the force of the torsion spring 148 in a counterclockwise direction, as in FIG. 1. The counterclockwise rotation of the latch plate 146 will cause the edge 160 to move to a position where it will not interfere with the edge 162 so that the member 22 may be rotated by the handle on the front surface 42 to a position which will cause the rods 26 and 28 as well as the finger 30 to move to a position which will not interfere with opening of the door. The rotation of the latch plate 146 while the switch and interlock mechanism 32 is in the ON position is permitted because of the slotted connection between the rod 166 and the latch plate 146 which is provided by the slot in the rod 166 that receives the screw 164.

The rotation of the handle 98 in a counterclockwise direction from the ON position in FIG. 3 will cause the lever 100 to actuate the OFF button 70 of the switch so that the switch is placed in an OFF condition, thereby interrupting the circuit to the wires 182 to the electrical device 18 within the enclosure 10. The movement of the handle 98 to the OFF position will also cause the pin 168 to rotate in a counterclockwise direction whereby the rod 166 is moved downwardly. The downward movement of the rod 166 will cause the latch plate 146 to rotate in a counterclockwise direction so that the edge moves out of the path of movement of the edge 162 so that the locking mechanism 20 may be rotated to a position which will permit the door to be opened. When the switch and interlock mechanism 32 is in the OFF position and the handle 98 is moved to the ON position, the lever 100 will actuate the ON button 72 of the switch and cause the pin 168 to move in an upward direction and thereby cause the rod 166 to be moved upwardly, as in FIG. 1. The upward movement of the rod 166 through the connection provided by the screw 164 will permit the latch plate 146 to be moved by the torsion spring 148 to the position wherein the edge 160 is positioned to interfere with the movement of the edge 162 and thereby prevent movement of the locking mechanism 20 to a position which will permit the door 14 to be opened.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. An interlock and switch-operating mechanism for a cabinet that has an opening closeable by a door and the door has a front surface, a rear surface, and an aperture extending between the front and rear surfaces, said mechanism comprising an operator assembly, a switch and a switch support assembly and a locking means including a reciprocal member that is movable adjacent the rear surface from a retracted position to an operative position for maintaining the door against movement from a position closing the opening when the member is in its operative position, said switch support and switch assembly including a member, a hinge mounting the member on the rear surface of the door for movement between two positions, a switched mounted on the hinged member, said switch having a pair of operating pushbuttons exposed at the front surface side of the door through the aperture when the hinged member is at a first one of its two positions and wire-connecting terminals that are readily accessible from the rear surface side of the door when the hinged member is at a second one of its two positions, and means for releasably maintaining the hinged member at said first one of the two positions, said operator assembly including a housing mounted on the front surface of the door and covering the aperture, means for selectively moving the pair of pushbuttons including a shaft rotatably carried by the housing, a handle carried on a portion of the shaft extending externally of the housing, a lever carried by a portion of the shaft disposed within a cavity in the housing with said lever having portions engaging the pushbuttons, and means on the portion of the shaft within the cavity connecting the shaft and reciprocal member for conjoint movement whereby movement of the handle to a predetermined position causes actuation of the switch and movement of the reciprocal member to the operative position for preventing movement of the door from the closing position.

2. An interlock and switch-operating mechanism for a cabinet that has an opening closeable by a door and the door has a front surface, a rear surface, and an aperture extending between the front and rear surfaces and a locking means including a member that is movable adjacent the rear surface from a retracted position to an operative position for maintaining the door against movement from a position closing the opening, said mechanism comprising an operator assembly, a switch and a switch support assembly and means including an interlock member movable to an operative position for preventing movement of the locking means member from the operative position, said switch and switch support assembly including a member, a hinge mounting the member on the rear surface of the door for movement between two positions, a switch mounted on the hinged member, said switch having a pair of operating pushbuttons exposed at the front surface side of the door through the aperture when the hinged member is at a first one of its two positions and wire-connecting terminals that are readily accessible from the rear surface side of the door when the hinged member is at a second one of its two positions, and means for releasable maintaining the hinged member at said first one of the two positions, said operator assembly including a housing mounted on the front surface and covering the aperture, means for selectively moving the pair of pushbuttons including a shaft rotatably carried by the housing, a handle carried on a portion of the shaft extending externally of the housing, a lever carried by a portion of the shaft disposed within a cavity in the housing with said lever having portions engaging the pushbuttons and means on the portion of the shaft within the cavity connecting the shaft and interlock member for conjoint movement whereby a movement of the handle to a predetermined position causes actuation of the switch and movement of the interlock member to the position for preventing movement of the locking member from said first one position.

3. The mechanism as recited in claim 12 wherein the operator assembly and the switch support assembly are respectively secured to the front and the rear surface of the door by threaded fasteners that have headed portions engaging portions of the switch support assembly and threaded portions ex tending in threaded openings in the housing.

4. The mechanism as recited in claim 12 wherein the interlock member is a rodlike member that is provided with an adjustment for adjusting the operating length of the interlock member.

5. The mechanism as recited in claim 4 wherein the interlock member is connected to a rotatable member that is biased by a spring to a position preventing movement of the locking member from the operative position.

6. The mechanism as recited in claim 5 wherein the interlock member is connected to the rotatable member through a connection which will permit the rotatable member to be rotated independently of the interlock member to its retracted position when the interlock member is positioned to maintain the interlock member in the operative position.

7. The mechanism as recited in claim 6 wherein the rotatable member has a portion extendin to be accessible from the front surface side of the door so t at the rotatable member may be moved to its retracted position when the door is closing the opening.

8. The mechanism as recited in claim 12 wherein the operator assembly is provided with a means which will accept a hasp of a lock to selectively maintain the handle against movement from either of two positions.

9. The mechanism as recited in claim 12 wherein the connection between the shaft and the interlock member is provided by a pin that is received in an opening in the interlock member.

10. The mechanism as recited in claim 12 wherein the locking means includes a handle that is accessible from the front surface side of the door and the interlock means is arranged to prevent movement of the handle to a position wherein the locking member is in a retracted position when the interlock member is in its operative position.

@2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,621,161 Dated November 16, 1971 Inventor) Armand G. Mueller, Orval C. Best and William H. Schmelin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

001. 4, line 26, for "16" read -106; line 41, for "position" read --positicns--'. C01. 6, line 70, for "switched" read --switch--. Col. 8, lines 7, 13, 32, 36 and &0, each occurrence, for the numeral "12" read ---2---.

Signed and sealed this 8th day of August 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. An interlock and switch-operating mechanism for a cabinet that has an opening closeable by a door and the door has a front surface, a rear surface, and an aperture extending between the front and rear surfaces, said mechanism comprising an operator assembly, a switch and a switch support assembly and a locking means including a reciprocal member that is movable adjacent the rear surface from a retracted position to an operative position for maintaining the door against movement from a position closing the opening when the member is in its operative position, said switch support and switch assembly including a member, a hinge mounting the member on the rear surface of the door for movement between two positions, a switched mounted on the hinged member, said switch having a pair of operating pushbuttons exposed at the front surface side of the door through the aperture when the hinged member is at a first one of its two positions and wireconnecting terminals that are readily accessible from the rear surface side of the door when the hinged member is at a second one of its two positions, and means for releasably maintaining the hinged member at said first one of the two positions, said operator assembly including a housing mounted on the front surface of the door and covering the aperture, means for selectively moving the pair of pushbuttons including a shaft rotatably carried by the housing, a handle carried on a portion of the shaft extending externally of the housing, a lever carried by a portion of the shaft disposed within a cavity in the housing with said lever having portions engaging the pushbuttons, and means on the portion of the shaft within the cavity connecting the shaft and reciprocal member for conjoint movement whereby movement of the handle to a predetermined position causes actuation of the switch and movement of the reciprocal member to the operative position for preventing movement of the door from the closing position.
 2. An interlock and switch-operating mechanism for a cabinet that has an opening closeable by a door and the door Has a front surface, a rear surface, and an aperture extending between the front and rear surfaces and a locking means including a member that is movable adjacent the rear surface from a retracted position to an operative position for maintaining the door against movement from a position closing the opening, said mechanism comprising an operator assembly, a switch and a switch support assembly and means including an interlock member movable to an operative position for preventing movement of the locking means member from the operative position, said switch and switch support assembly including a member, a hinge mounting the member on the rear surface of the door for movement between two positions, a switch mounted on the hinged member, said switch having a pair of operating pushbuttons exposed at the front surface side of the door through the aperture when the hinged member is at a first one of its two positions and wire-connecting terminals that are readily accessible from the rear surface side of the door when the hinged member is at a second one of its two positions, and means for releasable maintaining the hinged member at said first one of the two positions, said operator assembly including a housing mounted on the front surface and covering the aperture, means for selectively moving the pair of pushbuttons including a shaft rotatably carried by the housing, a handle carried on a portion of the shaft extending externally of the housing, a lever carried by a portion of the shaft disposed within a cavity in the housing with said lever having portions engaging the pushbuttons and means on the portion of the shaft within the cavity connecting the shaft and interlock member for conjoint movement whereby a movement of the handle to a predetermined position causes actuation of the switch and movement of the interlock member to the position for preventing movement of the locking member from said first one position.
 3. The mechanism as recited in claim 12 wherein the operator assembly and the switch support assembly are respectively secured to the front and the rear surface of the door by threaded fasteners that have headed portions engaging portions of the switch support assembly and threaded portions extending in threaded openings in the housing.
 4. The mechanism as recited in claim 12 wherein the interlock member is a rodlike member that is provided with an adjustment for adjusting the operating length of the interlock member.
 5. The mechanism as recited in claim 4 wherein the interlock member is connected to a rotatable member that is biased by a spring to a position preventing movement of the locking member from the operative position.
 6. The mechanism as recited in claim 5 wherein the interlock member is connected to the rotatable member through a connection which will permit the rotatable member to be rotated independently of the interlock member to its retracted position when the interlock member is positioned to maintain the interlock member in the operative position.
 7. The mechanism as recited in claim 6 wherein the rotatable member has a portion extending to be accessible from the front surface side of the door so that the rotatable member may be moved to its retracted position when the door is closing the opening.
 8. The mechanism as recited in claim 12 wherein the operator assembly is provided with a means which will accept a hasp of a lock to selectively maintain the handle against movement from either of two positions.
 9. The mechanism as recited in claim 12 wherein the connection between the shaft and the interlock member is provided by a pin that is received in an opening in the interlock member.
 10. The mechanism as recited in claim 12 wherein the locking means includes a handle that is accessible from the front surface side of the door and the interlock means is arranged to prevent movement of the handle to a position wherein the locking member is in a retracted position when the interlock member is in its operative position. 